i think it is a very sweet idea, however jewellery is very personal, and especially an engagement ring, i think i would let her choose her own, and if they cannot afford it right now ,so be it, i waited five years to get mine, we could not get one at the time, just a rather in expensive wedding band.

It also sounds like she has unique taste, and maybe would like something very simple and plain, just judging from your comments.

I see it quite differently than Karen and Donna, i would hate someone else's ring even if it did have sentimental value, i would feel i just had to accept it and wear it , even if i hated it,where it means something to you and your son, for her it might have very little meaning at all, just my opinion,and it is a pretty ring, but might not be to her taste.

so obviously my vote was let her choose her own.